nvmet: add Command Set Identifier support

NVMe TP 4056 allows controllers to support different command sets.
NVMeoF target currently only supports namespaces that contain
traditional logical blocks that may be randomly read and written. In
some applications there is a value in exposing namespaces that contain
logical blocks that have special access rules (e.g. sequentially write
required namespace such as Zoned Namespace (ZNS)).

In order to support the Zoned Block Devices (ZBD) backend, controllers
need to have support for ZNS Command Set Identifier (CSI).

In this preparation patch, we adjust the code such that it can now
support the default command set identifier. We update the namespace data
structure to store the CSI value which defaults to NVME_CSI_NVM
that represents traditional logical blocks namespace type.

The CSI support is required to implement the ZBD backend for NVMeOF
with host side NVMe ZNS interface, since ZNS commands belong to
the different command set than the default one.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/admin-cmd.c

@@ -162,15 +162,8 @@ out:
 	nvmet_req_complete(req, status);
 }
 
-static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
+static void nvmet_get_cmd_effects_nvm(struct nvme_effects_log *log)
 {
-	u16 status = NVME_SC_INTERNAL;
-	struct nvme_effects_log *log;
-
-	log = kzalloc(sizeof(*log), GFP_KERNEL);
-	if (!log)
-		goto out;
-
 	log->acs[nvme_admin_get_log_page]	= cpu_to_le32(1 << 0);
 	log->acs[nvme_admin_identify]		= cpu_to_le32(1 << 0);
 	log->acs[nvme_admin_abort_cmd]		= cpu_to_le32(1 << 0);
@@ -184,9 +177,30 @@ static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
 	log->iocs[nvme_cmd_flush]		= cpu_to_le32(1 << 0);
 	log->iocs[nvme_cmd_dsm]			= cpu_to_le32(1 << 0);
 	log->iocs[nvme_cmd_write_zeroes]	= cpu_to_le32(1 << 0);
+}
+
+static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
+{
+	struct nvme_effects_log *log;
+	u16 status = NVME_SC_SUCCESS;
+
+	log = kzalloc(sizeof(*log), GFP_KERNEL);
+	if (!log) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	switch (req->cmd->get_log_page.csi) {
+	case NVME_CSI_NVM:
+		nvmet_get_cmd_effects_nvm(log);
+		break;
+	default:
+		status = NVME_SC_INVALID_LOG_PAGE;
+		goto free;
+	}
 
 	status = nvmet_copy_to_sgl(req, 0, log, sizeof(*log));
-
+free:
 	kfree(log);
 out:
 	nvmet_req_complete(req, status);
@@ -613,6 +627,12 @@ static void nvmet_execute_identify_desclist(struct nvmet_req *req)
 			goto out;
 	}
 
+	status = nvmet_copy_ns_identifier(req, NVME_NIDT_CSI,
+					  NVME_NIDT_CSI_LEN,
+					  &req->ns->csi, &off);
+	if (status)
+		goto out;
+
 	if (sg_zero_buffer(req->sg, req->sg_cnt, NVME_IDENTIFY_DATA_SIZE - off,
 			off) != NVME_IDENTIFY_DATA_SIZE - off)
 		status = NVME_SC_INTERNAL | NVME_SC_DNR;
@@ -621,6 +641,17 @@ out:
 	nvmet_req_complete(req, status);
 }
 
+static bool nvmet_handle_identify_desclist(struct nvmet_req *req)
+{
+	switch (req->cmd->identify.csi) {
+	case NVME_CSI_NVM:
+		nvmet_execute_identify_desclist(req);
+		return true;
+	default:
+		return false;
+	}
+}
+
 static void nvmet_execute_identify(struct nvmet_req *req)
 {
 	if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
@@ -628,13 +659,31 @@ static void nvmet_execute_identify(struct nvmet_req *req)
 
 	switch (req->cmd->identify.cns) {
 	case NVME_ID_CNS_NS:
-		return nvmet_execute_identify_ns(req);
+		switch (req->cmd->identify.csi) {
+		case NVME_CSI_NVM:
+			return nvmet_execute_identify_ns(req);
+		default:
+			break;
+		}
+		break;
 	case NVME_ID_CNS_CTRL:
-		return nvmet_execute_identify_ctrl(req);
+		switch (req->cmd->identify.csi) {
+		case NVME_CSI_NVM:
+			return nvmet_execute_identify_ctrl(req);
+		}
+		break;
 	case NVME_ID_CNS_NS_ACTIVE_LIST:
-		return nvmet_execute_identify_nslist(req);
+		switch (req->cmd->identify.csi) {
+		case NVME_CSI_NVM:
+			return nvmet_execute_identify_nslist(req);
+		default:
+			break;
+		}
+		break;
 	case NVME_ID_CNS_NS_DESC_LIST:
-		return nvmet_execute_identify_desclist(req);
+		if (nvmet_handle_identify_desclist(req) == true)
+			return;
+		break;
 	}
 
 	nvmet_req_cns_error_complete(req);

drivers/nvme/target/core.c

@@ -682,6 +682,7 @@ struct nvmet_ns *nvmet_ns_alloc(struct nvmet_subsys *subsys, u32 nsid)
 
 	uuid_gen(&ns->uuid);
 	ns->buffered_io = false;
+	ns->csi = NVME_CSI_NVM;
 
 	return ns;
 }
@@ -877,10 +878,14 @@ static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
 		return ret;
 	}
 
-	if (req->ns->file)
-		return nvmet_file_parse_io_cmd(req);
-
-	return nvmet_bdev_parse_io_cmd(req);
+	switch (req->ns->csi) {
+	case NVME_CSI_NVM:
+		if (req->ns->file)
+			return nvmet_file_parse_io_cmd(req);
+		return nvmet_bdev_parse_io_cmd(req);
+	default:
+		return NVME_SC_INVALID_IO_CMD_SET;
+	}
 }
 
 bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
@@ -1102,6 +1107,17 @@ static inline u8 nvmet_cc_iocqes(u32 cc)
 	return (cc >> NVME_CC_IOCQES_SHIFT) & 0xf;
 }
 
+static inline bool nvmet_css_supported(u8 cc_css)
+{
+	switch (cc_css <<= NVME_CC_CSS_SHIFT) {
+	case NVME_CC_CSS_NVM:
+	case NVME_CC_CSS_CSI:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 {
 	lockdep_assert_held(&ctrl->lock);
@@ -1121,7 +1137,7 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 
 	if (nvmet_cc_mps(ctrl->cc) != 0 ||
 	    nvmet_cc_ams(ctrl->cc) != 0 ||
-	    nvmet_cc_css(ctrl->cc) != 0) {
+	    !nvmet_css_supported(nvmet_cc_css(ctrl->cc))) {
 		ctrl->csts = NVME_CSTS_CFS;
 		return;
 	}
@@ -1172,6 +1188,8 @@ static void nvmet_init_cap(struct nvmet_ctrl *ctrl)
 {
 	/* command sets supported: NVMe command set: */
 	ctrl->cap = (1ULL << 37);
+	/* Controller supports one or more I/O Command Sets */
+	ctrl->cap |= (1ULL << 43);
 	/* CC.EN timeout in 500msec units: */
 	ctrl->cap |= (15ULL << 24);
 	/* maximum queue entries supported: */

drivers/nvme/target/nvmet.h

@@ -83,6 +83,7 @@ struct nvmet_ns {
 	struct pci_dev		*p2p_dev;
 	int			pi_type;
 	int			metadata_size;
+	u8			csi;
 };
 
 static inline struct nvmet_ns *to_nvmet_ns(struct config_item *item)

include/linux/nvme.h

@@ -1504,6 +1504,7 @@ enum {
 	NVME_SC_NS_WRITE_PROTECTED	= 0x20,
 	NVME_SC_CMD_INTERRUPTED		= 0x21,
 	NVME_SC_TRANSIENT_TR_ERR	= 0x22,
+	NVME_SC_INVALID_IO_CMD_SET	= 0x2C,
 
 	NVME_SC_LBA_RANGE		= 0x80,
 	NVME_SC_CAP_EXCEEDED		= 0x81,